Clinical evaluation of balance Flashcards
What does the integration of the 3 things that make up balance (Vestibularsystem, vision and proprioception) allow us to do?
- Know where we are in the world.
- Gaze Stabilisation
What is the clinical Testing you do for balance disorders?
HISTORY: can usually diagnose from this! Don’t do if history if English isn’t their 1st language.
Ear Exam
Eye movement
Head Thrust
Fukunda stepping test
Dix Hallpike
Lab tests:
Audiogram, optokinetics, calorics, computerised head thrust, vEMP
What to ask in a full balance history examination?
- True Vertigo or not: if ‘the world feels like it’s moving’ (dizzy is just dizzy)
- Episodic nature
- Duration of vertigo: 1 min, hours, days
- Precipitating Factors
- head movement
- Loud noise
- diving
- migraine
- Associated factors
- migraines
- tinnitus
- hearing loss
- aural fullness
What is this, and how does this relate to the human anatomy
This is a builders Spirit level that has a moving bubble, which tells us we are off balance.
We ahve a similar thing in our balance system, but instead we have a cupula with embedded nerve fibres that goes horizontal, vertical and 45 degrees, that lets us know where we are!
What planes are the utricule and saccule in?
Utricle = horizontal plane
Saccule = vertical plane
These use the force of gravity relatively to the calcium crystals to tell you how you’re moving
What is the Vestibulo-ocular reflex?
There is a basal firing rate (both sides firing the same), when you turn left, the left side fires a little more, and the right side fires a little less due to the depol/hyper polarising of nerve fibres within the cupule being moved by the endolymph fluid eventually contracting the left medial rectus and the right lateral rectus!
This causes our eyes to move away-from the direction of movement!
This compensates for the fact that we are constantly moving, so this works like an ‘anti-motion camera process’
- VOR stabilizes images on the retina
- Goal: eye movement is equal and opposite to head movement!
‘COWS’
What does COWS stand for
Cold
Opposite
Warm
Same
If we put warm water in it stimulates same side
Cold water stimulates opposite side
Describe Gaze Stabilisation?
When you turn you head to one sid, due to the vesitbulo-ocular reflex we have a compensatory turn in the opposite direction → allows us to keep our “eyes on the prize” and focus on somethin even when our heads moving!
**note if you keep your head still and try follow a moving piece of paper, this is muuuch harder to read as this reflex is much slower!
Peripheral vestibular malfunction usually means….
Reduced function!!
- EG: sudden reduction of right inner ear function, will cause eyes to go quickly to the left, then sloooowly back to the right.
Therefore it’s ‘COWS cold’, quick nystagmus to the left, then slow move back to the right.
What will an otolithic crisis (eg menieres disease) cause?
HIGHER CENTRES ⇒ Dizziness (vertigo)
EYE MUSCLES ⇒ Nystagmus
LIMB MUSCLES ⇒ Ataxia
An episode of this
After a while if you get them up and about (hard to do), you get a cerebellum clamp that allows the patients brain to recognise the faulty signal and they can compensate!
What is Nystagmus of the eyes?
Rhythmic oscillation of the eye with a fast and slow phase.
‘Jerk’ Nystagmus: direction of the fast phase, eg left nystagmus is fast phase to the left (left beating nysatgmus)
A left beating nysatgmus means there’s either:
- hyperactivity in the left ear
- Hypofunction in the right (more common)
Mostly hypofunction of the opposite side,
eg; a pathology in the right ear → left beating nystagmus
Describe the Head thrust Test
- Grasp patients head, tilt down 30 degrees
- Instruct patient to fixate on nose
- Rapidly rotate head 15-20 degrees one side, then the other
- Eyes should remain on nose (despite sudden head movements)
- Watch for a ‘catch-up saccade’ a corrective movement back to nose
What is the cold Calorics?
- Patient lying down, LSCC up
- COLD water cause endolymph to become dense and fall away
- this deflects the cupula away (inhibits ride side),
- Nystagmus fast phase to beat away!
A warm caloric is?
When the endolymoh is warmed, becomes less dense, rises and causes deflection of cupula towards (excitation)
Increases firing right ear, so nystagmus will beat towards the stimulation
What can cause nystagmus due to calorics in everyday situations?
- Cold ear drops
- Suctioning
- Ear syringing
- Mastoid cavity clean
These can cause nausea and vomiting!!
What is the Fistula test?
if there’s a hole in the vestibulare system, by putting pressure on your ear by pressing in front of the tragus you will put pressure on the vestibular system!
If not normal: vertigo, nausea etc
Describe the Fukuda Stepping test!
Patient closes their eyes and walk on the spot!.
Their vestibular system should be able to compensate, but if they have some kind of vestibular damage, they will start turning/rotating in the direction of injury.
(once you take away the visual input you can’t compensate!)
Describe the Dix Hallpike test **** important!
Shows if you’ve got BPPV!!
The Dix-Hallpike test determines whether vertigo is triggered by certain head movements, but moving your head at certain angles.
- Have paitent lying flat, with their head at 30 degrees and to the side.
- Check for nystagmus (needed to diagnose BPPV)
- Do again on opposite side
What is BPPV
Benign Paroxysmal Positional Vertigo
- 30% of 70year olds have
- Vertigo that is self-limiting, <1min (anything longer NOT BPPV)
- Associated with positions, rolling in bed, looking up bending over, turning quickly
- NOT associated with tinnitus or hearing loss!
Diagnosed by Dix Hallpike test
what is VEMP
Checking reflex that turns head towards a loud noise to text utricular and saccula function and the nerves associated with them
What two areas need to be managed with vestibular disorders?
And how can we do this?
The condition itself, and the vertigo!
We can do this by maximising the 2 other systems!
- Keeping eyes open ⇒ visual system
- Maximise contact with the environment ⇒ proprioception
take home points…
What’s going on?
Is she spinning or the world? the world so it’s true vertigo
Episodic? Yes
For how long? <1min
SO it’s BPPV!!!
What is decompensation?
Vestibular-visual mismatch (visual vertigo)
Commonly after a small vestibular insult, where in a busy visual environment → sensory overload → eyes go everywhere!
Occurs in supermarkets/busy environments
